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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Unsymmetry Spiked-Quantum Well Design and Electroabsorption Modulators Based on the InAlAs/InGaAlAs Material System

Li, Jheng-jian 28 June 2005 (has links)
Multiple-quantum-well (M.Q.W.) and quantum-confined-stark-effect (Q.C.S.E.) have been widely used in designing and fabricating electroabsorption modulators. In this paper, material InAlAs/InGaAlAs near 1500nm transition is used to be our target for designing and fabricating EAM due to its high band-offset ratio (electron to hole) and the strong exciton effect. A calculation model for quantum well absorption has been developed to design EAM active region. Asymmetrically inserting a thin-spiked potential barrier into wide Q.W. structure, the Q.W. can have high efficiency of Q.C.S.E. without lowing the electron-hole wave function overlap integral, causing high electroabsorption coefficient and optical modulation. Tuning material composition (~-0.4% tensile strain ) is also used for polarization independence characteristics. Traveling-wave EAM based on InAlAs / InGaAlAs material system is also fabricated and measured. Polarization independence 2~5 dB operation, low voltage swing of 1V for 15 dB extinction ratio, high-speed electrical-to-optical response with ¡V3dB bandwidth of >20GHz at 50£[ termination have been achieved showing high potential in broad band fiber optical communication.

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